This invention relates to the curing of particulate arylene sulfide polymer. In one of its aspects it relates to a two-step process for curing particulate arylene sulfide polymer. In another of its aspects it relates to the use of a polisher apparatus in the curing of the particulate arylene sulfide polymers.
Conventionally, the curing cycle for arylene sulfide polymer is carried out in a single vessel. This entails filling the vessel with uncured polymer, bringing the entire mass to curing temperature (heat-up time) and continuing the heating until the desired melt flow of the batch is obtained (curing time). In a commercial operation where tons of polymer are cured in a batch process a sizeable length of time is spent in just reaching the curing temperature, e.g. about 15-20 hours. After the curing temperature is reached an additional 20-50 hours can be used in curing the resin to the desired level. The instant invention resides in reducing the heatup time by interposing a preheating step on the process as described below. By largely eliminating the 15-20 hours heatup time in the curing vessel, the overall length of the curing cycle is reduced proportionally and a substantial increase in the overall curing capacity of the combined system is effected and compared to use of a curing vessel alone.
It is therefore an object of this invention to provide a method for curing arylene sulfide polymer in which the overall time associated with curing the polymer in a single vessel is reduced. It is another object of this invention to provide a two-step process for curing arylene sulfide polymer in which the first step advantageously uses the friction developed in a mechanical device for heating the polymer from ambient to curing temperature. It is another object of the invention to provide a method for curing arylene sulfide polymer in which the heating of the polymer from ambient temperature to curing temperature can be carried out on a continuous basis with the curing process then applied batch wise.
Other aspects, objects and the various advantages of this invention will become apparent upon studying this disclosure, the drawings, and the appended claims.